Clinical and animal studies of eyes with hypotony will be performed to evaluate the mechanisms of hypotony. Experimental models of ciliochoroidal detachment, retinal detachment, and cyclodialysis in monkeys have been developed which result in hypotony. Aqueous flow studies and episcleral venous pressure measurements will be performed in these models. In addition, aqueous flow by fluorophotometry will be measured in patients with hypotony. A drug combination of methacholine plus eserine has been shown to reverse the experimental hypotony. The mechanism of action of this drug combination will be studied.